This specification relates to digital information retrieval, and particularly to processing search results.
The Internet enables access to a wide variety of resources, such as video or audio files, web pages for particular subjects, book articles, or news articles. A search engine can identify resources in response to a user query that includes one or more search terms or phrases. The search engine ranks the resources based on their relevance to the query and importance and provides search results that link to the identified resources, and orders the search results according to the rank. One example search engine is the Google™ search engine provided by Google Inc. of Mountain View, Calif., U.S.A.
Often a user searches for high quality information sources for a particular topic, but provides queries that cause the search engine to identify resources that vary in quality and across topics. For example, a user that desires access to Usenet groups may be unaware of the website “groups.google.com”, which provides access to millions of postings of many Usenet groups. Furthermore, the user may be unaware of the term “Usenet”, and therefore may not know how to form a query that is an accurate expression of the information desired. Thus, the user inputs the query “discussions” as an initial query to a search engine and receives many search results that are of little interest to the user. The user may then revise the query to “user discussions”, and again receive search results that are of little interest. The user may continue to revise queries, entering queries in the following sequence: “user group discussions”, “on-line discussion groups” and “internet discussion groups”. After selecting several search results and doing some reading, the user becomes aware of the term “Usenet” and enters the query “Usenet groups.” In response to this query, the search engine provides a set of search results in which the top-rated search result links to groups.google.com.
While the search engine in the example above eventually finds an informative and high quality resource (i.e., the web page located at the uniform resource locator groups.google.com), the user nevertheless entered a series of queries and selected several search results before finding this resource.